1. Field of the Invention
The present invention relates to a semiconductor device production method and in particular, to a semiconductor device production method which can preferably be used for a photoresist pattern formation.
2. Description of the Related Art
In general, when forming a circuit pattern such as a semiconductor integrated circuit on a semiconductor substrate, a photoresist pattern is formed by a photolithography procedure shown in FIG. 3 and after this, various post-treatments are performed. The photolithography procedure includes: pre-treatment (S100); photoresist application onto a semiconductor substrate (S101) which has been subjected to the pretreatment; an exposure step (S102) for exposing a circuit pattern such as a semiconductor integrated circuit, onto the semiconductor substrate having the photoresist; and a developing step (S103) for developing the semiconductor substrate having the circuit pattern exposed.
Conventionally, a semiconductor substrate 1 is divided into a circuit pattern area 2 and a non-circuit pattern area 3, i.e., a photoresist remaining area where the photoresist film is to remain so as not to be exposed to light. Only the circuit pattern area 2 is exposed to light and after this the entire semiconductor substrate 1 is developed to form the circuit pattern.
However, when the aforementioned photolithography uses a chemically amplified photoresist, in the circuit pattern area 2, acid generated by exposure de-protects a protection group of the photoresist 4 and the surface of the photoresist 4 becomes hydrophilic while in a non-exposed area, i.e., the photoresist remaining area 3, the surface of the photoresist 4 remains hydrophobic. Accordingly, in the development step S103, as shown in FIG. 4, water or developing solution 5 is expelled by the photoresist remaining area 3 and gathered in the circuit pattern area 2.
As a result, the water or developing solution 5 is not uniformly placed on the circuit pattern area 2, which disables uniform development. Fluctuation of pattern dimensions of the circuit pattern area 2 at the pattern dimension measuring row 6 shown in FIG. 2 becomes greater toward the photoresist remaining area 3. That is, the uniformity of the pattern dimensions in the semiconductor substrate 1 becomes worse. This problem is also present in the wet etching processing when using an etching solution for wet-etching the semiconductor substrate 1 having a photoresist pattern formed.